Multi-path digital pre-distortion

An apparatus, comprising:

• a multiband digital predistorter engine having a first band path and a second band path;
• an input stage of the digital predistorter engine coupled to receive first input samples via the first band path and second input samples via the second band path;
• the input stage configured to provide first interpolated samples for the first input samples and second interpolated samples for the second input samples;
• the input stage further configured to provide first interpolated magnitudes for the first interpolated samples and second interpolated magnitudes for the second interpolated samples;
• a first pair of digital predistorters of the digital predistorter engine coupled to receive the first interpolated samples, the first interpolated magnitudes and the second interpolated magnitudes;
• a second pair of digital predistorters of the digital predistorter engine coupled to receive the second interpolated samples, the second interpolated magnitudes and the first interpolated magnitudes;
• and
• an output stage coupled to receive predistorted outputs from the first pair of digital predistorters and the second pair of digital predistorters and configured to provide a digital predistorted composite signal of the predistorted outputs from the first pair of digital predistorters and the second pair of digital predistorters.

An apparatus, comprising:

• a digital predistorter engine having a single band path;
• an input stage of the digital predistorter engine coupled to receive input samples via the band path;
• the input stage configured to provide first magnitudes and second magnitudes for the input samples;
• the input samples being for a two-dimensional nonlinear function;
• the first magnitudes and the second magnitudes each being linear transformations for a one-dimensional nonlinear function;
• a pair of digital predistorters of the digital predistorter engine coupled to receive the input samples, the first magnitudes, and the second magnitudes;
• and
• an output stage of the digital predistorter engine coupled to receive predistorted outputs from the pair of digital predistorters and configured to provide a digital predistorted composite signal of the predistorted outputs from the pair of digital predistorters.